A direct current-to-direct current (DC-DC) power converter is typically used to supply a desired voltage and current to an electronic system. The converter receives an input voltage and delivers a regulated voltage and current. Depending on the power requirements, the DC-DC power converter may be a stand alone device, a component of an alternating current-to-direct current (AC-DC) power converter, or a component of a DC-AC power inverter. Power converters are used in a wide range of applications that include, but are not limited to, high performance computing platforms, mobile platforms, medical platforms, electric and hybrid vehicles, space power systems, military power systems and renewable energy power conversion systems.
Power converters are based on a variety of technologies including switching converters and linear regulator converters. In general, switching DC-DC power converters have the advantage of higher energy efficiency when compared with linear regulator converters. However, the switching DC-DC power converter is usually larger than a linear regulator converter because the switching converter requires magnetic devices such as power inductors and/or a power transformer. In addition, switching converters require more switching power devices and control circuits when compared to linear regulator converters. Even with such shortcomings, switching power converters are widely used, especially when conversion efficiency is crucial.
Increasing the power density of a switching converter is desirable. Power density improvements for a switching power converter can be achieved by improving the efficiency of the converter and/or reducing the size of the converter. In general, increasing the power density is achieved by making smaller power inductor and/or power transformer, making smaller switching power devices, and changing converter architecture. New and less complex control mechanisms often reduce the number and size of components required for controlling the converter. Researchers and developers are continuously working on ways to increase the power density of a switching converter.
As integrated circuits (ICs) and other loads get smaller and distributed through a system, it is often necessary to place the switching power converter near an IC or a load in a distributed architecture. In addition, new ICs and loads perform more functions that often require more energy. If components of a system are battery powered, increasing the efficiency of a switching power converter extends battery life and/or saves energy. However, it is generally undesirable for a converter to achieve an increased power density if energy efficiency is decreased and/or regulation performance compromised.
Achieving a high power density for a converter generally allows for size reduction and less weight for the power converter and the system receiving power from the converter. The size and weight of a switching converter are considered critical for a variety of devices, such as personal portable electronic devices, devices for medical applications, and devices for space applications and military systems. Further, switching converters with increased energy density have less weight and will enhance performance of electric and hybrid vehicles.
It also is important to achieve higher energy/power conversion efficiency in order to save energy related to thermal issues and to increase reliability. By increasing energy efficiency of a converter, thermal management components, such as heat sinks and cooling fans, can have size reductions. Therefore, converter improvement leads to further size and weight reduction of an overall system.
In addition, it is desirable to improve regulation performance of power converters in order to avoid system operation malfunctioning. Accordingly, it is desirable to not only increase power density but also to improve regulation performance and energy/power conversion efficiency.